In general, in an excavating site or a mine for open-pit mining, a hydraulic excavator is used to perform a work in such a manner that a large amount of minerals, and earth and sand are excavated, and a large amount of the excavated minerals (crushed stones) are loaded on a large-sized transporter vehicle called a dump truck to be transported to an unloading area such as a port.
This dump truck is configured schematically of a vehicle body on which a loading platform (vessel) for loading objects to be transported is provided, an engine that is mounted on the vehicle body, an alternator that is driven by the engine to perform power generation, and an electric motor for traveling to which drive power is supplied based upon the power generation of the alternator.
Since the alternator and the electric motor generate heat at the time of driving the dump truck, the dump truck is provided with a cooling air supply device for supplying cooling air to the alternator and the electric motor. This cooling air supply device is configured schematically of a cooling air inlet port for taking in outside air as cooling air, a cooling air supply line for establishing connection between the cooling air inlet port, and the alternator and electric motor as cooling targets, and a cooling fan (blower) for sucking cooling air into the cooling air supply line from the cooling air inlet port (See, Patent Document 1).